The new FAN UNIT replacement for the Kenwood TS930S transceiver

This board is a aftermarked replacement for the original power supply fan, developed as a silent replacement for the original fan to improve the ventilation of the power supply.
The FAN UNIT is fixed with the four original screws through the holes for the original fan support frame, maintaining the original look of your transceiver.
The fan on this kit is always active, but the speed is controlled automatically. Therefore a thermal sensors detect the temperature of the airflow and adjust automatically the speed of the fans accordingly with a temperature controlled linear voltage regulator.
In addition, the minimum fan speed can be adjusted via a trimmer on the board (see also the "FAN SPEED" labeled trimmer hole on the back side).
To check the function of the fans, there is also a timer circuit that enable the fan at his maximum speed for a few seconds after the TS930 is turned on.

The fan used in this kit is standard size, so it's readily available and easy to find on the market as replacement part.
The power supply for this fan assembly is taken directly from 28VDC output of the POWER SUPPLY UNIT, mounted directly behind the heat sink.

Each FAN UNIT is shipped as preassembled and tested.

"TS930S FAN UNIT" Project webpage